In situ gasket moulding

ABSTRACT

The invention is a method for forming a gasket over an opening of a hollow form. The method comprises placing an unformed gasket ( 12 ) over a mould surface ( 14 ) having a shape in relief that is the shape to which the gasket ( 12 ) is to be formed. A hollow form ( 10 ) is placed onto the mould ( 13 ) so that the gasket ( 12 ) is held between the opening ( 11 ) of the hollow form ( 10 ) and the mould surface ( 14 ). Expanding foam ( 15 ) is located within the hollow form ( 10 ) so that the foam ( 15 ), as it expands, pushes against the gasket ( 12 ) to form it to the shape of the mould surface ( 14 ). This shape is retained upon setting of the foam. The invention greatly simplifies the manufacturing process of a hollow form ( 10 ) fitted with a gasket ( 12 ).

[0001] This invention relates to a method of forming a gasket on a hollow article during the process of filling the article with foam.

[0002] This application describes improvement to the external mirror assembly and method of manufacture described in the applicant's earlier International Patent Application PCT/AU00/00054. The disclosure contained in that specification is included by reference to this specification. This specification should be reviewed in conjunction with the disclosure contained in the above application.

BACKGROUND

[0003] Mirror heads are generally pivotally connected to supporting brackets which are in turn attached to motor vehicle bodies. The brackets are normally moulded components and are attached via threaded fasteners. They have a gasket or thin rubber sealing strip placed between the bracket and the body of the vehicle. This gasket forms a weather-proof seal between the vehicle and the bracket.

[0004] Traditionally, such gaskets are either pre-cut to the required shape or are injection moulded from rubber. They are either glued to the bracket or held in place during assembly.

[0005] This specification describes an improved method of providing either a gasket or seal for a component that is attached to another article. The invention could be suited to applications in other areas so the invention as described herein is not necessarily restricted to the application of mirror heads and attachment brackets.

SUMMARY OF THE INVENTION

[0006] In its broadest form, the invention is a method of forming a gasket over an opening of a hollow form comprising:

[0007] placing an unformed gasket over a mould surface having a shape in relief being the shape to which said gasket is to be formed;

[0008] placing said hollow form onto said mould so that said gasket is held between said opening of said hollow form and said mould surface, and

[0009] locating expanding foam material within said hollow form so that said foam pushes against said gasket to form it to the shape of said mould surface said shape being retained upon setting of said foam.

[0010] The pressure exerted by the foam while the hollow form is held against the mould is sufficient to cause the gasket material to deform to the required shape as defined by the mould. The hollow form is held against the mould as the foam cures so that when the product is released from the mould, the gasket retains the shape of the mould.

[0011] This process has the advantage of moulding the gasket to the required shape while at the same time using the foam to glue the gasket to the hollow form. The gasket also stops foam leaking out during the filling process. Also, the process avoids the need of forming the foam directly against a mould surface which would require use of a mould release agent. The avoidance of using any mould release agents is important, as residues of these agents may migrate to surfaces that require painting. This is not possible if the surface is contaminated with mould release agent.

[0012] Although this invention has numerous applications, a particular application described in this specification will be in relation to its use with foam filling of hollow forms such as mirror heads or mirror mounting brackets. Gaskets on such hollow forms perform a number of functions. For instance they are used to form a seal between the component and attachment point of the vehicle (to provide weather proofing), to provide a better fit to the vehicle and/or to improve the appearance of the joint.

[0013] In order to fully understand the invention as described above, a preferred embodiment will now be described. However, it should be realised that the scope of the embodiments described do not restrict the invention to the precise detail of the embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIGS. 1 to 6 show the production steps for foam filling of a mirror head incorporating a gasket over an opening on a mirror mounting bracket.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] As seen in FIG. 1, the process starts with a hollow form or article 10 having an opening 11. The article 10 is to be filled with expanding foam and it is also to have a gasket 12 formed across the opening 11. The gasket 12 is to be formed during the moulding process into the required shape. This is achieved using a mould 13 that has the required shape 14 in relief on the surface of the mould. The process comprises cutting or moulding the gasket 12 to the required shape. It is then placed against the mould 13 and held in place by the article 10 as shown in FIG. 4. Foam 15 is then injected into the cavity of the article 10. The foam 15 expands and applies pressure to the gasket 12 so that the gasket 12 forms the shape defined by the mould 13. This is shown in FIG. 5.

[0016] In addition to injecting the foam 15, the required amount of pre-mixed foam may be placed within the article 10 just prior to it being placed against the gasket 12 and mould 13.

[0017] After the foam 15 is set, the article 10 can be removed from the mould 13. The foam will adhere the gasket 12 to the article 10 and also maintain the required shape.

[0018] The article 10 is then ready to fit directly to either a motor vehicle body or some other fitting.

[0019] Clearly, this aspect of the invention provides a greatly simplified means of manufacturing an article with a pre-fitted gasket rather than having to assemble the article with the gasket at a later stage. Also it meets the requirements of sealing an article with an opening with is to be filled with foam. A combination of these features produces a useful and unique result.

[0020] Australian Patent No. 639105 titled “Spigot Type Bread-Away Mirror” and International Application No. AU00/00068 titled “Pivot With A Detent” describe pivot mechanisms that may be incorporated between a mirror mounting bracket and a mirror head. The disclosure of both of these specifications is incorporated in its entirety herewith. The pivot mechanisms disclosed in both of these specifications that may be used with the mounting bracket described in this invention.

[0021] Australian Patent Application No. 68997/98 titled “A mirror operating Mechanism” and International Application No. AU00/00009 titled “A mirror rotation mechanism” described electric power fold mechanisms which move a mirror head from its normal in use position to a parked position where the mirror head is rotated towards the body of the vehicle. Both of these inventions could be used with the mounting bracket described in this invention and the disclosure of both of these specifications is incorporated in their entirety within this specification.

[0022] International Patent Application No. AU00/00413 titled “method of producing a plastic moulded part including a film covering” discloses a method of forming a moulding component comprising an outer thin film component with an adhered moulded shell. This invention could be used to mould the hollow form component subject of this invention and the disclosure of this application is incorporated herewith in its entirety.

[0023] International Patent Application No. AU00/00815 titled “Load support for a wing mirror” describes a method of supporting a mirror head on a mounting bracket. This support could be incorporated on the mirror mounting bracket subject of this invention and the disclosure of this application is incorporated in its entirety herewith.

[0024] It would also be possible to incorporate other components with the mirror mounting bracket. Such components include electronic sensors such as proximity sensors to determine if the vehicle mirror is close to an obstruction, sensors that sense external temperature and humidity, and sensors incorporated with the car security system such as motion detectors. Other various electronic equipment may be incorporated into the mirror mounting brackets such as lights used to light the area around the vehicle, or lights that may be controlled from within the vehicle that enable the light to be moved so as to provide directional lighting. Speakers and microphones used to communicate to people external of the vehicle may also be incorporated as well as antennas for various apparatus such as mobile phones, GPS devices and other radio communication devices. In addition, transmitters may be incorporated into the mounting bracket which are used for controlling external objects such as garage doors or providing radio transmissions which may be used, for example, to track or locate the vehicle. Other electronic devices such as automatic toll payment systems or remote transaction systems may be incorporated into the mounting bracket to enable electronic registration of various toll payments.

[0025] Cameras may also be incorporated into the mounting bracket which are both forward and rearward looking which are designed to continuously digital images and to store those images either on command or as a result of an accident. Motion sensors can be used to determine the occurrence of an accident so that images before and after the event are stored. 

The claims defining the invention are as follows:
 1. A method of forming a gasket over an opening of a hollow form comprising: placing an unformed gasket over a mould surface having a shape in relief being the shape to which said gasket is to be formed; placing said hollow form onto said mould so that said gasket is held between said opening of said hollow form and said mould surface, and locating expanding foam material within said hollow form so that said foam pushes against said gasket to form it to the shape of said mould surface said shape being retained upon setting of said foam.
 2. A method according to claim 1 wherein said gasket sheet is pre-trimmed to correspond to the shape of said opening and the thickness of the wall of said hollow form.
 3. A method according to claim 1 wherein said hollow form comprises a vehicle mirror bracket.
 4. A formed gasket attached to a hollow form comprising: a hollow form having an opening, and a gasket located over said opening that is formed to a required shape by holding said gasket between a mould and said hollow form, where said mould surface has a shaped surface, being the shape to which said gasket is to be formed, and locating expanding foam material within said hollow form so that said foam pushes against said gasket to form it to the shape of said mould surface, said shape being retained upon setting of said foam.
 5. A formed gasket according to claim 4 wherein said gasket is shaped as required prior to fixing to said hollow form.
 6. A formed gasket according to claim 5 wherein said gasket has a peripheral edge that extends past the edge of said opening.
 7. A formed gasket according to claim 5 wherein said gasket has a peripheral ridge that locates within and around the edge of said opening.
 8. A gasket according to claim 4 wherein said hollow form comprises a bracket for a vehicle mirror.
 9. A method of forming a gasket substantially as herein described with reference to the accompanying drawings.
 10. A formed gasket substantially as herein described with reference to the accompanying drawings. 